Injustice: Gods Among Us - The Flash strategies, tips and basics
Dwn-Dwn+M (Running Man Stance) Fwd+M or Fwd+H is great for quick high/low mixups. note: *Not safe on block*
Back-Fwd+M (Lightning Charge) Really good to close gap. Relatively safe on block depending on how quick opponent's reversal attack.
Lightning Kick, Speed Dodge(MB) & Sonic Pound is safe on block
most of combo strings are safe on block depending on how quick opponents reversal attack. For exapmle: L-L or L-L-M & Back+M-M or Back+M-M-Fwd+H is safe on block
Jump+L, L-L-M xx Lightning Kick(MB), Dwn+M, F.Jump+L, H-M xx Lightning Kick(MB optional) - 38% dmg
Fwd+M-L xx Back Back+MB, Jump+H, H-M xx Lightning Kick(MB) - 41% dmg
Back+H or Fwd+H, F.Jump+M, L+H, L M xx Speed Zone - 40% dmg (this requires a stage with hazard knockback with the "L+H" input.
Fwd+M-L xx Lightning Kick(MB), Dwn+M, Time Loop, Lightning Charge x5, H-M xx Lightning Kick - 38% dmg (note: work way to corner)
Back+H, Fwd Dash, F.Jump+H, Dwn+M, Time Loop, Lightning Charge x4, H-M xx Speed Zone - 39% dmg (note: work way to corner)
Fwd+H, Time Loop, Lightning Kick x4, Back+M-M-Fwd+H xx Speed Zone - 58% dmg (note: Lightning Kick x5 is possible, but requires precise execution for 62% dmg)